The present invention relates to electrical resistors, and more particularly, to resistor configurations which enable the determination of the temperature coefficient of resistance (TCR) thereof.
It is sometimes desirable to employ a given electroconductive material for use as a resistor or heater because of certain properties that it may possess such as desirable values of resistivity and thermal coefficient of expansion, while the temperature coefficient of resistance of that material may be undesirable for its intended use. For example, the thermal coefficient of expansion, thermal conductivity and resistivity of silicon cause that material to be suitable for deposition on a low expansion glass-ceramic material for use as a heating element. However, the negative TCR of silicon necessitates a current limited power supply to avoid thermal runaway. In lieu of this relatively expensive type of power supply, it would be advantageous to prevent thermal runaway by modifying the TCR of the heating element.